Furnace wall structure



NOV. 1934-- w. F. KEENAN, JR.. ET AL 1,931,648

FURNACE WALL STRUCTURE Filed May 1, 1931 2 Sheets-Sheet 1 Nov. 20, 1934- w. F. KEENAN, JR., El AL FURNACE WALL STRUCTURE Filed'I-ziay 1, 1931 2 Sheets-Sheet 2 I LL 4o 29 INV TOR 6- fir/r A1TORN Y Patented Nov. 20, 1934 UNITED STA res PATENT OFFICE signors to Foster Wheeler Corporation, New York, N. Y., a corporation of New York Application May 1, 1931, Serial No. 534,234. 13 Claims. (01. 122-5) Our. invention relates to furnaces, particularly to water walls thereof, and especially to an improved refractory armor construction for water walls.

The general purpose of providing an armor for water walls is to prevent the fire from coming into direct contact with'the tubes and also to form a continuous flat or substantially continuous flat non-slagging wall made up of a plural.- ity of blocks having high heat conductivity.

These blocks being placed in contact with the tubes assure that substantially all of the heat absorbed by the wall is transferred to the water tubes and is thus usefully employed in heating or vaporizing the fluid within the tubes.

It has been proposed to provide armor block units, each made up of two members-having cylindrical tube receiving recesses and curved surfaces eccentric to' these' recesses. The blocks making up a unit are placed with the tube receiving recesses on adjacent water tubes and with the eccentric surfaces of the tube blocks in contact with each other. Tension means is employed to rotate or swing the blocks on the tubes and to wedge the blocks between and against the tubes due to the eccentric surfaces. While the close contact between the blocks and the tubes resulting from this wedging action assures 'a good heat transfer therebetween', we have found that proper adjustment of the blocks with respect to the tube 7 aggregate is difficult due to the tendency of the wedging action to separate or spread the tubes. In the present invention we provide means for aligning the tubes and preventing shifting of the tubes due to the wedging action while retaining all of the advantages derived from the use of this type of armor block unit.

These and further objects and advantages will be apparent from the following description considered in connection with the accompanying drawings, which are to be taken as a part of this specification and on which:

Fig.1 is a cross-sectional view of a portion of a boiler furnace provided with a water wall;

Fig. 2 is a view showing details of a water wall construction in accordance with the invention and taken on the line 2-2 of Fig. 1;

Fig.3 is across-sectional view of a portion of the furnace wall construction on enlarged scale;

line '4- 4 of Fig. 2;

Fig. 5 is a cross-sectional view taken on the line 5-5 of Fig. 2; and

Figs. 6 to 8 are perspectivev views, partially Fig. 4 is a cross-sectional view taken on the,

in cross-section of certain of the elements of the water wall. 1

Referring to the drawings, Fig. 1 shows a well known type of water tube boiler having a furnace chamber 10 enclosed by vertical walls, including a rear water wall 11. A series of vertically extending water tubes 12 passthrough wall 11. The lower ends of tubes 12 communicate with a header 13 while the upper ends communicate with a header 14, bothof these headers being located outside of the furnace. It is the usual practice to pass water through tubes 12 either before it is introduced into the boiler proper or by thermosiphon circulation conduits connected to the boiler proper. Any type of boilerv may be used, that illustrated having water tubes 15 and a steam block units'18 made of cast-iron or other suitable refractory material. The details of the block units in acocrdance 'with my invention are shown in Figs. 2 through 5. Each block unit 18 comprises a pair of block members 19 and 20. Members 19 and 20 are identicalin form. Each member comprises a front fire face 21 of substantially rectangular shape and an adjacent convex hearing or contacting-surface 22. The bearing surface of block 19 is in contact with the bearing surface of block 20 when the blocks. are in position on the tubes. Each block is also provided with a cylindrical tube receiving recess 23 of substantially the same diameter as the water tubes 12. Each recess 23 is of sufficient extent to extend around more than one quarter of the perimeter of a tube and hence when block members of'adjacentblock units are in place on a tube more than one half of the surface of the tube is in contact with the blocks. The bearing surfaces 22 are curved and may be cylindrical and are eccentric with respect to the tube receiving recesses 23. In the form shown, the surfaces 22 are drawn about centers tube receiving recess is cut away at the rear portion thereof as is indicated at 24. A pair of lips -or abutments 25 extend from the block proper on either side of and adjacent to the central part of each block. The central part of each block between abutments 25 is formed with a semicylindrical recess 26 to receive the head of an' eye-bolt 2'7, the shank of which extends between the abutments 25. A portion of the block adjacent to the tube receiving recess is cut away between the abutments 25, as is'shown at 28 in order to make room for a rigid backing member, as will be explained.

In the preferred form shown, the rigid backing members are of three different types. Rigid backing member 29 comprises a rectangular metallic piece provided with a flange 30 extending around the four sides thereof. The face of member 29 opposite fiange 30 is provided with two tube receiving recesses 32 formed principally by projecting lips 33. At either end of member 29 there is formed a portion of tube receiving recess 34. Rigid backing member 35 is similar to-member 29 except that it is shorter and is provided with two tube receiving recesses 36 and one partial recess 37. Rigid member 38 is similar to member 35 except that it is provided with only one tube receiving recess and one partial tube receiving recess. The purpose of having three different types of rigid backing members is in order that, when they are placed in position on the tubes as is shown in Fig. 2, the ends of the backing members in adjacent rows will be staggered.

In assembling our preferred form of water wall the block units comprising block members 19 and 20 are placed in position on pairs of adjacent tubes by placing their respective tube receiving surfaces on the tubes and rotating each block around the tubes until their bearing surfaces 22 come in contact with each other. Eye-bolt 27 is then placed in position between abutments 25 on the pair of block members and a pin 40 is passed through the substantially cylindrical recess formed between corresponding abutments on the two blocks, through the eye of the eye-bolt and through the cylindrical recesses formed between the other two corresponding abutments. Pin 40 may be provided with a head 41 in order that it as the bearing surfaces 22 on the blocks are eccentric with respect to the surfaces of'the tube receiving recesses 23, there-will; be a cam action between the two blocks which wedges them together and in close contact with the tubes. This force of tension also draws the backing member against the tube and tends to displace the tube which is received in the'partial tube receiving recess at the end of the backing member. However, this tendency to displace the tube is overcome bythe fact that the rigid member in the adjacent row is of such a-length that its end is out of alignment with the end of the rigid members in the rows at either side thereof. Thus,

in Fig. 2, when rigid member 38 in the lowermost row shown in the drawings is drawn against the tubesby tightening nut 43 it will have a tendency to displace the second tube from the right hand side of the figure towards the left. However, this tube is held in position by means of rigid member 29 in the second row from the bottom. This member 29 has a tendencyto displace the fourth tube towards the left but this tendency is resisted by members 29 in theb'ottom and third from the bottom rows. It will thus be seen that the greatest unsupported length of any tube is the distance between two alternate rows of backing members and hence the tubes cannot be displaced when the backing members are drawn against them.

The curved portion 44 of tubes 12 are provided with a modified form of block and backing member, as is shown in Fig. 4. These block units comprise blocks 45 and 46 which are identical in form and are provided with bearing surfaces Bolts 51 pass through the apertures in members '49 and engage the threaded apertures 48 in blocks 45 and 46 and, when tightened, draw the member 49 and blocks 45 and 46 against the is resisted by the rigid members 29, 35 and 38 .in the topmost row and by the tubesupporting means 56. Tube supporting means 56 comprises a member 57 set into the furnace wall and. straps 58 secured thereto and extending around the tubes. 1

Thus it will be seen that the present invention provides means for obtaining close contact of the refractory blocks with the tubes by wedging the blocks against each other and between the tubes while preventing the spreading of the tubes due to this wedging action. While we have described preferred means for carrying out this invention, it is to be understood that thesemore' or less specific means are for the purpose of illustration only and that we are not to be limited except by the appended claims considered in the light of the prior art.

What I claim is:

1. The combination with spaced tubes, of armor blocks therefor and'a plurality of rigid backa ing members secured to said blocks and arranged in rows extending across said tubes, each of said backing members being arranged to engag'e more than two adjacent tubes and being independent of and unconnected with the other backing members and being formed with a plurality of tube receiving recesses and means securing said backing members to said tubes, backing members in adjacent rows being arranged in I staggered relationship with each other.

2. The combination with spaced tubes, of a plurality of rigid backing members arranged in rows extending across said tubes, each of said backing members being arranged to engage more than two adjacent tubes and being independent of and unconnected with the other backing members and beingformed with a plurality of tube receiving recesses, a plurality of block units comprising two block members having curved tuberecesses and curved contacting surfaces eccentric thereto, and tension engaging said block members and said backing members, the backing members in adjacent rows being arranged in staggered relationship with each other.

3. The combination with spaced tubes, of a plurality of rigid back members arranged in rows extending across said tubes, each of said backing members being arranged to engage more than two adjacent tubes and being independent of and unconnected with the other backing members and being formed with a plurality of tube receiving recesses, a plurality of block units comprising two block members having curvedtube recesses and curved contacting surfaces eccentric thereto, and said block members having abutments, and stress means acting between said abutments and said backing members and operative to swing said block members on the tubes to wedge the block units by cam action of the eccentric contacting surfaces, the backing members in adjacent rows being arranged in staggered relationship with each other.

4. The combination with spaced tubes, of a plu-. rality of rigid backing members arranged in rows extending across said tubes, each of said backing members being arranged to engage more than twoadjacent tubes and being independent of and unconnected with the other backing members and being formed with a plurality of tube receiving recesses, a plurality of block units having curved tube recesses,and means for clamping said block units and said backing members on said tubes, said backing members in adjacent rows being arranged in staggered relationship with each other.

5. The combination with spaced tubes, of a plurality of rigid backing members arranged inrows extending across said tubes, each of said backing members being arranged to engage more than two adjacent tubes and being independent of and unconnected with the other backing members and being formed with a plurality of tube receiving recesses, a plurality of block units having curved tube recesses, and means for securing said block units and said backing members together in clamped relationship with said tubes, said backing members in adjacent rows being arranged in staggered relationship with each other.

6. The combination with spaced tubes, of rigid backing members arranged in rows extending across said tubes, each backing member being independent of the other backing members and comprising a flanged metal piece having tube receiving recesses and tube engaging projections on the front side thereof and apertures therein, each backing member being arranged to engage more than two adjacent tubes, a plurality of block units each comprising two block members having curved tube recesses and contacting surfaces opposite the tube recesses and rear recesses for receiving said tube engaging projections, and tension members passing through the apertures in the backing members and operative to pull the block members and the backing members into engagement with the tubes, the backing members in adjacent rows being arranged in staggered relationship with each other. L

7. The combination with spaced tubes, of rigid backing members arranged in rows extending across said tubes, each backing member being independent of the other backing members and comprising a box-like metal piece having forward tube engaging projections and having apertures therein, each backing member being arranged to engage more than two adjacent tubes, a plurality of block units each comprising two block members having curved tube recesses and contacting surfaces opposite the tube recesses and rear recesses for receiving said tube engaging projections, and tension members passing through the apertures in the backing members and compris ing threaded members and nuts and operative to pull the block members and the backing members into engagement with the tubes, said nuts being disposed in said rigid backing members, the backing members in adjacent rows being arranged in staggered relationship with each other.

8. Armor block structure adapted to be secured to spaced tubes comprising a plurality of armor block units, each unit comprisingtwo block members each member having a curved tube recess and a curved surface eccentric with respect to the tube recess and in contact with the curved surface of the other member, a plurality of rigid backing members having substantial contact with the tubes and spaced from and independent of each other and extending transversely of the tubes and arranged in spaced rows, each of the backing members arranged to engage more than two adjacent tubes, and tension members engaging the block members of each armor block unit and a backing member and adapted to pull the block members and the backing members into engagement with the tubes, thereby tending to spread adjacent tubes apart due to the action of the curved contacting surfaces of the block members, the backing memberstbeing so applied to the tubes that the joints between the ends of the backing members in adjacent rows are staggered with respect to each other 9. Armor block structure adapted to be secured to spaced tubes comprising a plurality of armor block units, each unit comprising two block members each having a curved tube recess, a plurality of rigid backing members having substantial contact with'the tubes and. spaced from and independent of each other and extending transversely of the tubes and arranged in spaced rows, each of said rigid backing members arranged to engage more than two adjacent tubes, and tension members engaging the block members of each armor block unit anda backing member and adapted to pull the block members and the backing members being so applied to the tubes that the joints between the ends of the backing members in adjacent rows are staggered with respect to each other.

10. An armored wall structure comprising a row of spaced tubes, a plurality of rows of armor block units in contact with the tubes, a plurality of transversely extending rows of rigid backing members in contact with the tubes, and means engaging the block units and therigid backing members for securing said units and members to the tubes, said block units tending to displace the tubes upon being secured thereto, the backing members having sufiicient contact with the tubes to resist the said tendency to displace the same, rigid backing members in each row having engagement with more than two adjacent tubes and being independent of other backing members, the ends of the backing members in adjacent rows being out of alignment whereby the tubes are secured against transverse displacemnt with respect to each other.

11. An armored wall structure comprising a row of spaced tubes, a plurality of rows of armor block units in contact with the tubes, a plurality of transversely extending rows of rigid backing members in contact with the tubes, and means of alignment whereby the tubes are secured against transverse, displacement with respect to each other.

12. An armored wall structure comprising a row of spaced tubes, a plurality of rows of armor block units in contact with the tubes, a plurality of transversely extending rows of rigid backing members in contact with the tubes, and tension means engaging the block units and the rigid backing members for securing said units and members to the tubes, said block units tending to displace the tubes upon being secured thereto, the backing members having sufiicient contact with the tubes to resist the said tendency to displace the same, rigid backing members in each row having engagement with more than two adjacent tubes and being independent ofother backing members, the ends of the backing members in adjacent rows being out of alignment whereby the tubes are secured against transverse displacement with respect to each other.

13. ,An armored wall structure comprising a row of spaced tubes, a plurality of rows of armor block units in contact with the tubes, a plurality of transversely extending rows of rigid backing members in contact with the tubes, and means engaging the block units and the rigid backing members for securing said units and members to the tubes, said blockunits tending to displace the tubes upon being secured thereto, the backing members, having sufficient contact with the tubes to resist. the said tendency to displace the same, rigid backing members in each row having engagement with more than two adjacent tubes and being independent of other backing members and 

